java - Sms ContentObserver onChange() fires multiple times

Question

I know this question has been asked multiple times, but nobody has been able to come up with a working answer from what I have seen.

Im working on an app to intercept text messages and depending on the sending #, pop up with a custom alert. I have it working beautifully with a broadcast receiver, however if the user has goSms installed the onReceive() method is never called as goSms aborts it before it ever reaches my app.

To get around this, Im trying a content observer on content://sms/ Its working just fine, however the onChange() is called twice, with exactly the same parameters. Ive tried to check the time stamps, but they are the same, as is the type and every other parameter I have set.

From what I've seen, this is a common issue, but not one that I've seen answered anywhere.

    @Override
public void onChange(boolean selfChange) {
    super.onChange(selfChange);
    querySMS();
}

protected void querySMS() {
    Cursor cur = getContentResolver().query(u, null, null, null, null);
    cur.moveToNext(); // this will make it point to the first record, which is the last SMS sent
    String type = cur.getString(cur.getColumnIndex("type"));
    String body = cur.getString(cur.getColumnIndex("body")); //content of sms
    String add = cur.getString(cur.getColumnIndex("address")); //phone num
    if (type.equals("1")) {
        if (add.equals(Test.SENDER)) {              
            String[] bodys = body.split(" ", 7);
            if (bodys[0].equals("test")) {
                test = true;
            }
            cat = bodys[1];
            level = bodys[2];
            urgency = bodys[3];
            certainty = bodys[4];
            carrier = bodys[5];
            message = bodys[6];
            final Intent intent = new Intent(context, AlertActivity.class);
            Bundle b = new Bundle();
            b.putString("title", cat);
            b.putString("certainty", certainty);
            b.putString("urgency", urgency);
            b.putString("level", level);
            b.putString("message", message);
            b.putBoolean("test", test);
            intent.putExtras(b);
            intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
            TelephonyManager manager = (TelephonyManager)context.getSystemService(Context.TELEPHONY_SERVICE);
            carrierName = manager.getNetworkOperatorName();
            if (carrierName.replaceAll(" ", "").equals(carrier)) {

                context.startActivity(intent);
            } else {
                //testing
                Toast.makeText(context, carrierName.replaceAll(" ", ""), Toast.LENGTH_LONG).show();
            }
        }
    }
}

Because of the onChange() being fired twice, Im getting two alerts as well. I cannot for the life of me figure out a way around this.

Answer 1

If the two are identical:
store each message recv'd
compare it to previous messages recv'd
if not found, process
if found, discard the message

The life of the messages stored should be infinitesimal, a little circular buffer of 5 messages should be fine.